The elucidation of the mechanism involved in the monoamine uptake in the cerebral capillaries has been investigated by using 3H metaraminol, a norepinephrine analogue which is not metabolized by either COMT or MAO. These studies have shown that the 3H metaraminol is taken up by K ion- and Na ion-dependent, carrier-mediated process in the isolated cerebral microvessels similar to the one reported in the neurons. This project is completed.